Portable power operated hammer



June 9, 1931. J. R. HILSTAD 1,809,340

PORTABLE POWER OPERATED HAMMER Filed July 1, 1925 s Sheets-Sheet 1 I INVENTOR. JOHN E. HILSTAD F ww z jrci A TTORNEYS.

June 9,- 1931. J. R. HILSTAD 1,809,340

PORTABLE POWER OPERATED HAMMER Filed July 1, 1925 s Sheets-Sheet 2 INVENTOR.

JOHN E. HILSTAD A TTORNEYS.

June 9, 1931. J. R. HILSTAD PORTABLE POWER OPERATED HAMMER 3 Sheets-Sheet 3 Filed July 1, 1925 HN R. H/Ls TAD .iTTORJV'EY mm l \WJY a 7X 4 3 a 4 8 WW1; W I

M\ & ilitiii m m I I- I .717%7/ Ill mm B 2 /4! El 1 m om i Q v.2 m& N: M M. Q Q T's 25 vention and will then point out t Patented June 9, 1931 UNITEDL STAT/ES PATENT o 101m no! mm, or wnrrma cans-01mm, assren'oa or TWO-THIBDS enoaen e. GRIFFITH m or omz-rnran rro many at. camnnnnmr, no'rn or WHI'ITITB CALIFORNIA.

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Application filed July 1,

My invention relates to and has for its purpose the provision of a power operated hammer which is capable of being manually moved over sheet metal work, such as motor 5 vehicle fenders, in a manner to remove therefrom with facility and dispatch all undulations, so thatany sheet of metal, no matter Y how badly dented, can be quickly restored to its ori inal form.

It is a so a purpose of m inventlon to provide a hammer of the a ve described character'in whichthe hammer action can be varied at the will of the operator merely by increasing or decreasing the pressure with 15 which the tool is applied to the work.

A. further object of my invention is the provision of a metal bending hammer which em-- bodies a mechanism that permits the hammer per se to be. rendered inactive but which 80 allows the continued use of the driving shaft of the mechanism for other purposes, such as the driving of a buffing or grinding wheel.

I will describe only two forms of portable power operated hammer embodying my ine novel features thereof in claims.

In the accompanying drawmgs,

Figure 1 is a view showing in side elevation and partly in section one form of hammer embodying my invention in applied position to a piece of work;

Figure 2 is an enlarged view showing in front elevation the hammer shown in Figure 1 with the cover plate removed; Figure 3 is a vertical fragmentary sectional view taken on the line 3-3 of Figure 2; Figure 4 is an enlarged fragmentary'sec-v tional view of a portion of the hammer shown in Figure 3 in position with relation to a piece of work; Figure 5 is a fragmentary-sectional view of the hammer shown in Figure 3 with theham mer per se in inactive position. I Figure 6 is a view sh; wing in vertical longitudinal section another form of hammer embodying my invention.

Figure 7 is a vertical transverse sectional view taken on the line 77 of Figure 6. 60 Figure 8 is a view on a reduced scale show-.

. e 1925. Serial m. 40,904.

ing inside elevation the hammerfshown in Fi ures 6 and 7. Y

imilar reference characters refer, to simishown as-comprising a casing preferably cast integral with a tubular handle 16 adapted to be gripped in moving the hammer as a unit over a piece of work. Mounted for reciprocating movement within the casing 15 is a hammer including a shank 17 on the lower end of which is formed an enlarged head 18. Between its ends theshank 17 is provided with a flattened portion 19 formed with a slot 20 through which extends a shaft 21. The flattened portion 19 is provided with an abutment 22 adapted to be engaged by a cam 23 fixed to the shaft 21 and of the form shown in Figure 2. The abutment 22 is normally urged downwardly toward the cam through the medium of a coiled .expansiblespring-24 mounted in the casing between the head 18.

and a flange 25 formed interiorly of the casing adjacent its point of connection with the. handle 16. The upper endof the shank 17 is threaded as indicated at 26 to receive lock nuts27 for maintainin a coiled expansible spring 28 within a poc et 29 formed in the casing, the spring 28 being provided for the purpose of preventing the abutment 22 from impinging against the shaft 21 when such abutment is out of engagement with the cam 23. An opening 30 is formed in the wall" of the pocket 29 through which a pin 31 (Figure 5) can be extended to engage within an opening 32 formed in the hammer shank 17 to secure the hammer insuch elevated posi- 1;

tion that the abutment 22 cannot be engaged by the cam 23.

The shaft 21 as clearly shown in Fi re '3 is journaled in bushings 33, 34 and 35, t e bushmg 35 being formed integral with a plate 36 detachably secured by means of screws37 to the forward side of the casing 18. The rear end of the shaft 21 is formed with a slot 38 .by whichit can be operatively connected to a flexible shaft 39, Figure 1, so as tobe continuously driven in one direction from any suitable source of power, such as electric mov tor (not shown). The opposite end of the shaft 21 is also slotted as indicated at 40 for connection with a bufiing wheel or grinding wheel or any other form of tool, so as to drive the latter when the hammer is not in use or when the hammer is held in the position shown in Figure 5. To facilitate attaching the shaft 39 to the inner end of the shaft 21 and the tools above mentioned to the forward end of the shaft 21, the bushings 33 and 35 are exteriorly threaded.

The hammer so far described is adapted to be used in conjunction with a die 41 carried by a yoke secured to the handle 16 and comprising a fixed arm 42 and a movable arm 43 pivotally connected to the fixed arm at the oint indicated at 44. The movable arm 43 is provided at its free end with a socket 45 into which extends a head 46 formed on. the die 41, the head being secured in the socket by means of a cotter in 47. By means of the yoke justdescribed it is possible to vary the spaced relation of the die 41 with respect to the hammer head 18 so as to accommodate therebetween metal work of different degrees of thickness. 1

For the purpose of varying the hammering action of the tool so as to effectively remove from a sheet of metal dents or protrusions of different depths or heights, the working end of the casing is provided with a yieldably supported extension in the form of an annular collar 48. This collar 48 is normally projected from the end of the casing by means of a coiled expansible spring 49 mounted in a pocket 50 formed between the reduced end of the casing and an annular sleeve 51 which threadedly engages the casing. The inner wall of the sleeve 51 is formed with an annular shoulder 52 to accommodate an annular 'lip' 53 formed in the upper end of the collar as illustrated'in Figure 1 and the arm 43 held by the operator against one side of the work, and the shaft 21 continuously rotating in a clockwise direction as when viewed in Figure 2, it will be clear that the cam 23 is rotated to cause. its spiral periphery to intermittently wipe the abutment 22 and in so doing to elevate the hammer head 18 against the tension of the spring 24. As the abutment 22 rides off the spiral edge of the cam 23,it will be clear that the hammer shank is released so as to respond to the expansive action of the spring 24, thereby driving the hammer head 18 downwardly into contact with the work. Under this rapid elevation and release of the hammer head, it will be manifest that the work is subjected to a hammering action which operates to flatten the work on the die 41, thus removing from the work any dents or protrusions. t .will be understood that when the hammer is operating on curved work, curved dies can be substituted for the flat die shown in Figure 1,-so that the normal original curvature of the work can be restored.

In the fully projected position of the collar 48, as shown in Figure 3, it will be manifest that the hammer head 18 is held out ofcontact with the work, and that by gradually exerting pressure on the casing in the direction of the work, the collar 48 will be elevated, thus lowering the hammer head into contact with the work so as to subject the latter to its hammering action. As the pressure is increased, the downward or hammering stroke of the head 18 is shortened so that when released by the cam 23 the spring 24 will exert its maximum expansive action on the head 18, thus effecting the maximum hammering action on the work. In this manner, the intensity of the hammering action can be increased or decreased at will, thus rendering the tool applicable to sheet metal work of different degrees of thickness and having various forms of dents and protrusions.

Should it be desired to use the shaft 21 for purposes other than driving the hammer, it will be clear that by elevating the hammer shank and securing the same in the position shown in Figure 5 any tool can be applied to the forward end of the shaft 21 and driven thereby. 4

Referring now to Figures 6, 7 and 8, I have here shown another form of hammer embodying my invention which is particularly designed for the mechanical actuation of drills, buifing wheels and similar tools used in the repairin of fenders in addition to the actuation of a ammer, and in such .manner that the tools can be driven at difierent constant speeds. In this embodiment of my invention, a sectional casing is provided at both sides and closed at its rear side by a cover plate 61 formed on the forward end of a tubular handle 62. The front side of the casing is closed by a front cover plate 63, the plate and easing being secured to the rear cover plate by means of bolts 64 as clearly illustrated in Figures 7 and 8. The lower end of the casing 60 is provided with a threaded neck 66 to which is secured the upper end of a sleeve 67.

A hammer comprising a head 68 is mounted for reciprocating movement within the sleeve 67 and is formed with a threaded extension 69 engaging within a socket 70 on the lower end of a shank 71. This shank 71 is movable ing in secured-within the neck by a s'crew 73 and having therein waste or other H purpose ofl11=bcricating the shank 71 in its reciprocating movement.

The u perendof the witlra atten'ed connecting head 75 having a slot 76 through which extends a stub axle 77; ar wheel 78 is r'otatablyv mounted onone' 'en of the axle 77-which carries a cam 79'siniilar in'construction to the cam 23 in thejfirst form of my invention. The connecting head 75 carries a roller 80 urged downwardly so as to have constant on gement with the periphery of the cam 79 y means of a spring 81 interposed between the threaded neck 66 andthe hammer head 68 so as to ur e the latter downwardly in the sleeve 67 and thereby exert a similar action on the shank 71 and the connecting head 75. The roller is maintained against lateral displacement from the cam 79 by means of a spring 82, the expansible action of which operates to urge a pair of plates 83 against the connecting head 75 so that the latter in turn is urged toward the cam 79. This spring 82 also serves, to center the shank 71 in the casing, as will be'understood. i

As shown in Figure 6, the spring 82bears against a gear wheel 84 rotatable on the other end of the stub axle 77 and provided .with. a tool connecting socket 85 rotatable in a collar 86 formed integral with the cover plate 63 and exteriorly threaded to receive a cap 87. The gear wheels 78 and 84 constantly mesh with-pinions 88 and 89, respectively, mounted on a shaft 90. The pinion 88 is keyed to the shaft 90 while the pinion 89 is rotatable on the shaft and is normally urged against the cover plate 63 by means of a spring 91.

The tubular handle 62 contains a driven shaft 92, the rear end of which is provided with an extension 93 having a socket 94 receiving a head 95 of a flexible shaft 96, the head being formed with a slot 97 into which extend ins 98 carried by the socket 94 and retaine in position by'a sleeve 99 threaded in the end of the handle and providing a sup-' port for the confronting end of a caslng 100 for the flexible shaft 96.

At its forward portion the driving shaft 92 is provided with a shaft extension 101 secured to the main portion of the shaft bya collar 102 and formed with longitudinally extendribs 103 which work in grooves 104 of a pair of pinions 105 and 106 permanently connected by a grooved collar 107. By this construction it will be seen that upon rotation of the driving shaft 92, the two pinions 105 and 106 are rotated with the shaft but at the same time are capable of longitudinal movement on the shaft extension 101 to permit the engaging and disengaging ,of the pinions 88 and 89,

respectively. These pinions 105 and 106are shank is formed 7 adagitedto be manually moved through the 108 engaging within the. material v74 saturated withoil for the groove of the collar 107 and'provided with a stud 109 which extends upwardly through a me. ium of a yoke slot 110 'in the .casing 60. Plates 111 are secured to the stud 109 to move with the latter, and the arrangement of the plates is such as to at all times close the slot 110 to prevent the escape of a lubricant therethrou h, it bein understood that the entire casing 1s filled wit oil for the purpose of lubricating the moving 7 in Figure 7, and the two pinions 105 and 106 out of mesh with the pinions 88 and 89, it

will be clear that only the tool connecting socket 113 is driven, and by removing the cap 114 a drill chuck 115 such as shown in Figure 8 or a bufling wheel (not shown) may be applied to the socket and thus driven thereby. When driving a tool in this manner, the hammer head 68 remains at rest so that the ,manipulationof the tool can be effected without interference from the operation of the hammer. Y

When desiring to drive the hammer, the stud 109 is moved rearwardly from the position shown in Figure 6 to cause the pinion 105 to mesh with the pinion 88 thereby operatively connecting the gear wheel 78 with the driving shaft 92. With the gear vwheel 78 driven in this manner the cam-7 9 is constantly rotated in a counter-clockwise direction as when viewed in Figure 7 thereby intermittent- 1y elevating the connecting head 75 against theaction of the spring 81 so as to impart a reciprocating movement to the hammer head 68 and in such manner as to suddenly release the hammer head after each elevating movement to permit the spring to force the hammer head downwardly thereby efl'ecting the hammering action. In order that the hammer head may operate in the corners of fenders and other forms of work, the sleeve 67 is recessed as indicated at 67a, the edge of the recess being chamfered as shown.

When desiring to actuate the tool connecting socket 85 without actuating the hammer the stud 109 is moved forwardly from the position shown in Figure 6 to cause the pinion 106 to mesh with the pinion 89 thereby o eratively connecting the gear Wheel 79 wit the drivin shaft 92. It will, of course, be understood t at through this connection with the driving shaft a reduction in rotational speed of the socket 85 is effected as compared with the rotational speed of the socket 113. It will thusbe seen'that the operator of employing either tool connecting socket to rotate the two at the same spee as the driving shaft 92 or at a reduced speed.

Although I have herein shown and described only two forms of portable power operated hammer embodying my invention, it

is to be understood that various changes and modifications may be made herein without de- V parting from the spirit of the invention and the s lrit and scope of the appended claims.

I c aim as my invention: 1. In combination a power operated hammer including a hammer element, a yokesecured to the hammer and including a movable member pivotally connected t the yoke and a die secured to the movable member and supported in coacting relation to the hammer element.

2. A power operated hammer comprising a hammer element mounted for movement and'normally urged to one extreme position, means for moving the hammer element to an-' other extreme position and suddenly-releasing the same, and means-normally urged to a rojected position, which, with respect to the direction of'movement of the hammer element in striking a blow, is in advance of the active face of the hammer element, and by which the efi'ective movement of the hammer element in relation to a varied at will.

3. A power operated hammer comprising a hammer element mounted for movement and normally urged to one extreme position,

element into active contact means for moving the hammer element to another extreme position and suddenly releasing the same, and a yieldably supported extension adapted to engage a pace of work and normall .urged to a rojected position in advance o the active ace of the hammer element said extension movable to a retracted position in response to pressure exerted against the work so as to bring the hammer with the work, whereby the efi'ective movement of the I hammer element with relation to the work can be varied at will.

' JOHN ROY HILSTAD.

piece of work can be 

